The efficiency of high throughput screening can be improved if libraries with huge diversity could be characterized for bioactivity in preliminary rounds of screening. There are currently no instruments that can characterize the bioactivities of combinatorial libraries.Intelligent Optical Systems (lOS) proposes to develop a new, inexpensive, optical instrument, based on a label less detection principle, for the rapid characterization of the bioactivities of combinatorial libraries. The proposed instrument will have sensitivities comparable to surface plasmon resonance and will measure binding events in real time. The instrument will be able to distinguish high affinity specific interactions from low affinity nonspecific binding. The proposed device consists of a laser light source, a biochip, a flow cell, a pair of detectors, and a computer for analyzing the detector's output. In Phase I, lOS will demonstrate the feasibility of using this instrument as a tool for characterizing the bioactivity of combinatorial libraries by testing the performance of the instrument through stable protein-protein interaction monitoring, transient enzyme-substrate reactions, and small molecule protein interaction.